Transcript 2007 하계 방학 실습

전자의료시스템 및 실습
PWM
구환
경희대학교 전자정보대학 동서의료공학과
PWM
• Description
- PWM(Pulse Width Modulation)
- 일정한 전압에 일정한 주기를 갖는 펄스 열에서 High 레벨의 펄스
폭이 사용자가 지정한 값으로 바뀌는 파형
- PWM 주기(period)
- PWM 주파수(frequency)
- Duty Cycle: 전체 주기에서 하이 레벨의 펄스 폭의 %
- 아날로그 신호 레벨을 디지털 신호 레벨로 묘사하는 데 매우 유용
- PWM의 듀티는 아날로그 신호의 에너지를 의미
- DC 모터를 제어하거나 특정 아날로그 파형을 PWM 파형으로 변환
가능
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
PWM Waveform
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
Generation of PWM Outputs Using the GP Timers
• PWM Operation
- To generate a PWM output with a GP timer, a continuous up- or
up-/down- counting mode can be selected.
- To set up the GP timer for the PWM operation, do the following:
1. Set up TxPR according to the desired PWM(carrier) period
2. Set up TxCON to specify the counting mode and clock source,
and start the operation
3. Load TxCMPR with values corresponding to the on-line
calculated widths(duty cycles) of PWM pulses
- TxPR = (PWM period / GP timer input clock) – 1
- Continuous up- : Asymmetric Waveform
Continuous up-/down- : Symmetric Waveform
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
Compare Unit Block Diagram
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
Register Setup for Compare Unit Operation
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
PWM Circuits Block Diagram
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
Dead-Band?
• Description
- 순간적이지만 H-브리지 회로에서 쇼트 회로가 발생하는 것을 막기
위한 장치
- PWM 레벨 전환 시 약간의 지연 시간을 두어 쇼트 회로가 만들어지
는 상황을 피하도록 하는 기능
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
Output Logic Block Diagram
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
Asymmetric PWM Waveform Generation
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
Symmetric PWM Waveform Generation
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea
Quadrature Encoder Pulse(QEP)
2007 Summer Seminar
Impedance Imaging Research Center, Kyung Hee University, Suwon, South Korea